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Lesson 3 Information repositories
Objective Describe the use of a database in an eBusiness context

Information Repositories

An eBusiness solution will need to refer to and create stored information such as inventory data, customer details, transactional data, and so on. This information must be stored in information repositories. The information repositories consist of databases, Database Management Systems (DBMS), and supporting file systems that store and maintain the information for the eBusiness applications. All or part of this repository may be an existing system previously and/or still used for legacy systems[1] in the organization.
There are several factors that can influence the choice of a database in an eBusiness solution. They are described in thetable below.

Factors influencing the choice of a database

Factors influencing database choice Description
Requirements of the application Some applications may place specific requirements on the database based on their interface to it. If the application is already defined/selected, then the application may dictate the choice of database.
Performance and security objectives vs. cost Future scalability, required performance, and security objectives should be set and maintained as much as possible.
Integration of existing legacy systems If the organization already has a database, it may prove too costly, difficult, or unnecessary to migrate to a different system.
Company standards and preferences Although much care must be taken in using these as selection criteria, it often is the case that a company with existing IT systems and/or senior executives with a history of using specific solutions will impose restrictions on the choices available.
Increased performance and better system security tend to carry a larger price tag.

Standards

Fortunately, there are sets of standards that can help to simplify some of the connectivity and incompatibility issues that may arise from the selection of the database.
Examples of these standards and technologies include:

Open Database Connectivity (ODBC)

Open Database Connectivity (ODBC) is a method developed by Microsoft to enable any applications that support ODBC to access any ODBC-compliant database. This is access is achieved with a driver layer that receives and interprets data queries from the application and then submits them to the DBMS for execution.

Common Object Request Broker Architecture (CORBA)

Common Object Request Broker Architecture (CORBA) is an architecture developed by the Object Management Group (OMG) for open-systems inter-object communication. '' CORBA enables objects, that is, pieces of program code, to communicate with each other regardless of the language they are written in or where they reside. CORBA uses a protocol called Internet Inter-Object Protocol (IIOP) to enable the communication of complex objects over the World Wide Web. CORBA can be used with various operating systems.

Other Types of Middleware

Distributed Component Object Model (DCOM): Distributed Component Object Model (DCOM) is an extension of COM (Component Object Model) developed by Microsoft to allow applications to access objects. DCOM used to be called Network OLE (Object Linking and Embedding) and extends the COM model to work across networks. Unfortunately, DCOM is presently restricted to Windows operating systems. Remote Method Invocation (RMI)
Remote Method Invocation (RMI): Remote Method Invocation (RMI) is the solution developed by Sun's Javasoft division. RMI enables object communication, but is much simpler than CORBA or DCOM and works purely with Java objects.

Advantages of these Frameworks

These frameworks and standards may afford the benefits listed in the table below:
Advantages Description
Greater cost savings:Applications and database systems can be developed and bound with off-the shelf components.
Increased productivity:Various components can be separately developed and some objects can be re-used.
More flexibility:Systems can more easily be extended and changed, and technologies like CORBA can enable legacy data to be "wrapped" with an interface layer thatconforms and communicates with systems that are more modern.

Information Repositories - Exercise

In the next lesson, we'll identify the considerations for selecting or building a server. Click the Exercise link below to complete an exercise that reviews the application of database technologies in an eBusiness context.
Information Repositories - Exercise

[1]Legacy systems: Legacy systems support legacy applications.